Replacement of a structurally damaged membrane

Abstract

Disclosed is a method of replacing a structurally damaged membrane after determining which membrane in a multiple unit filter press membrane electrolytic cell is damaged in response to cell operating conditions and monitorings indicating a problem exists.

Having thus described in the invention, what is claimed is: 
     
       1. A method of replacing a structurally damaged membrane in a filter press membrane electrolytic cell containing electrolyte having an anode bus, a cathode bus, an anolyte infeed manifold, a catholyte infeed manifold, a deionized water infeed, a brine infeed, a product caustic outlet, a product chlorine outlet, and a plurality of anodic and cathodic electrodes, each pair of anodes and cathodes being sandwiched about a membrane, comprising: a. electrically disconnecting the electrolytic cell from the electrical power source;   b. disconnecting and sealing the brine and deionized water infeed;   c. draining the electrolyte from the electrolytic cell;   d. determining the location of the electrode adjacent the structurally damaged membrane;   e. removing the catholyte infeed manifold;   f. removing the anolyte infeed manifold;   g. removing the anode bus;   h. removing the cathode bus;   i. placing the electrolytic cell in a horizontal position to form a cell stack;   j. removing the back plate from the electrolytic cell;   k. connecting a lifting fixture to the electrode immediately above the electrode adjacent the structurally damaged membrane;   l. breaking the stack apart into two units by raising the lifting fixture connected to the electrode immediately above the electrode adjacent the structurally damaged membrane;   m. inspecting the structurally damaged membrane;   n. replacing the structurally damaged membrane;   o. reassembling the cell stack into one unit; and   p. reassembling the electrolytic cell and reconnecting the cell electrolytic and electrical connections.   
     
     
       2. The method according to claim 1 wherein the step of determining the location of the electrode adjacent the structurally damaged membrane further comprises: a. filling the cathodes with a test liquid;   b. having the test liquid pass through a structurally damaged membrane into the adjacent anode; and   c. observing the test liquid in the anode adjacent the structurally damaged membrane.   
     
     
       3. The method according to claim 2 further comprising feeding the test liquid into the cathodes through the catholyte infeed manifold. 
     
     
       4. The method according to claim 2 further comprising using water as the test liquid. 
     
     
       5. The method according to claim 2 further comprising using a brine as the test liquid. 
     
     
       6. The method according to claim 2 further comprising using caustic as the test liquid. 
     
     
       7. The method according to claim 1 wherein the step of determining the location of the electrode adjacent the structurally damaged membrane further comprises: a. filling the anodes with a test liquid;   b. having the test liquid pass through a structurally damaged membrane into the adjacent cathode; and   c. observing the test liquid in the cathode adjacent the structurally damaged membrane.   
     
     
       8. The method according to claim 7 further comprising feeding the test liquid through the anolyte infeed manifold into the anodes. 
     
     
       9. The method according to claim 7 further comprising using water as the test liquid. 
     
     
       10. The method according to claim 7 further comprising using a brine as the test liquid. 
     
     
       11. The method according to claim 7 further comprising using caustic as the test liquid. 
     
     
       12. The method according to claim 1 further comprising using a sling, a sling spreader and a plurality of channels as the lifting fixture. 
     
     
       13. The method according to claim 12 further comprising the steps of: a. fastening the bottom of each of the channels to lifting lugs on the electrode frame immediately above the electrode adjacent the structurally damaged membrane; and   b. fastening the top of each of the channels to the sling.   
     
     
       14. The method according to claim 13 further comprising using a lifting means to raise the cell stack to break the cell stack apart into two units so that the topmost unit is supported by the sling and the remaining lower unit contains the structurally damaged membrane. 
     
     
       15. The method according to claim 14 further comprising removing a gasket and lubricating strip adjacent a structurally damaged membrane prior to inspecting the structurally damaged membrane. 
     
     
       16. The method according to claim 15 further comprising breaking the remaining lower unit of the cell stack apart at the adjacent membrane-electrode interface prior to replacing the structurally damaged membrane to check for damage prior to replacing the structurally damaged membrane. 
     
     
       17. The method according to claim 16 further comprising the steps of: a. replacing the gasket and lubricating strip; and   b. replacing the electrode to reestablish the adjacent membrane-electrode interface.   
     
     
       18. The method according to claim 1 further comprising the steps of: a. replacing the anolyte infeed manifold with a valved infeed manifold that permits the isolation of the individual anodes;   b. filling the anodes and the cathodes with a test liquid while maintaining a predetermined positive cathode to anode differential in fill height level;   c. stopping the filling of the anodes and the cathodes with test liquid when the cathodes are filled;   d. isolating each individual anode by using the shut-off valves on the valved infeed manifold;   e. having a test liquid pass through a structurally damaged membrane into the adjacent anode; and   f. observing the test liquid level in each of the anodes to determine which anode has the liquid level rising to locate the anode adjacent the structurally damaged membrane.   
     
     
       19. The method according to claim 1 further comprising the steps of: a. replacing the catholyte infeed manifold with a valved infeed manifold that permits the isolation of the individual cathodes;   b. filling the anodes and the cathodes with a test liquid while maintaining a predetermined positive anode to cathode differential in fill height level;   c. stopping the filling of the anodes and the cathodes with test liquid when the anodes are filled;   d. isolating each individual cathode by using the shut-off valves on the valved infeed manifold;   e. having a test liquid pass through a structurally damaged membrane into the adjacent cathode; and   f. observing the test liquid level in each of the cathodes to determine which cathode has the liquid level rising to locate the cathode adjacent the structurally damaged membrane.   
     
     
       20. A method of breaking apart a filter press membrane electrolytic cell to inspect and replace a gasket or a membrane, the cell being filled with electrolyte and having an anode and cathode bus, cell back plates, an anolyte and catholyte infeed manifold, a brine infeed, a deioinized water infeed, a product caustic outlet, a product chlorine outlet, and a plurality of anodic and cathodic electrodes, each pair of anodes and cathodes being sandwiched about a membrane and having a lubricating strip between at least each cathode and each membrane, comprising; a. electrically disconnecting the electrolytic cell from the electrical power source;   b. disconnecting and sealing the brine and deionized water infeed;   c. draining the electrolyte from the electrolytic cell;   d. determining the location of the gasket or membrane to be inspected;   e. removing the anolyte infeed manifold and catholyte infeed manifold;   f. removing the anode bus and cathode bus;   g. placing the electrolytic cell in a horizontal position to form a cell stack having a top and a bottom with the gasket or membrane to be inspected closest to the top of the cell stack;   h. removing the cell end plate nearest the top of the cell stack;   i. connecting a lifting fixture to the electrode immediately above the electrode adjacent to the gasket or membrane to be inspected;   j. breaking the cell stack apart into two units by raising the lifting fixture and the top unit of the cell stack immediately above the electrode adjacent the gasket or membrane to be inspected;   k. inspecting the gasket and membrane;   l. replacing the lubricating strip and the gasket;   m. reassembling the cell stack into one unit; and   n. reassembling the electrolytic cell and reconnecting the cell electrolyte and electrical connections.   
     
     
       21. The method according to claim 20 further comprising replacing the membrane prior to replacing the lubricating strip and the gasket.